In conventional tape feeders for pick and place machines, the components are typically stored in pockets in reeled tape. A cover or shutter seals each components in its pocket. In these typical tape feeders, the shutter that contains the part during transport of the tape is opened to expose the parts for pick-up by a vacuum tip shortly after indexing. In high speed applications (on the order of 50 milliseconds for 4 millimeters of index length), the part becomes unstable and oftentimes changes attitude or completely flips over in its surrounding pocket after the shutter is opened. This, of course, makes it difficult or impossible to retrieve the component.
To overcome these disadvantages, a flat shutter was developed, as seen in U.S. Pat. No. 4,740,136. An access slot or notch with a width narrower than that of the chip and wider than that of the vacuum tip is formed in the flat shutter. A vacuum tip fits through the access slot to hold the component at the proper attitude for pick-up. Once the chip is captivated, the shutter is withdrawn and the chip is lifted from the pocket. However, this device has the disadvantage that it requires the tip to have a smaller cross-sectional area than the surface area of the upper face of the chip. Therefore, extremely small chips cannot be handled with this device.
Another shutter mechanism is shown in application Ser. No. 07/127,991, now U.S. Pat. No. 4,838,452 commonly assigned herewith, the contents of which are incorporated herein by reference. The device disclosed in this application uses a finger projecting from the pick-and-place head. The finger engages a shutter actuating lever, which laterally displaces the shutter to provide access to the component.